Respiratory Case Histories - Case 13
A 150 lb., 62-year-old man had a chronic productive cough,exertional dyspnea, mild cyanosis, and marked slowing of forcedexpiration. His pulmonary function and laboratory tests follow:
| Frequency | 16 breaths/min |
| Alveolar ventilation | 4.2 L/min |
| Vital capacity (VC) | 2.2 L |
| Functional residual capacity (FRC) | 4.0 L |
| Total lung capacity (TLC) | 5.2 L |
| Maximum inspiratory flow rate | 250 L/min |
| Maximum expiratory flow rate | 20 L/min |
| PaO2 | 62 mm Hg |
| PaCO2 | 39 mm Hg |
Pulmonary function tests after bronchodilator therapy:
| Frequency | 16 breaths/min |
| Alveolar ventilation | 4.35 L/min |
| VC | 2.4 L |
| FRC | 4.0 L |
| TLC | 5.2 L |
| Maximum inspiratory flow rate | 250 L/min |
| Maximum expiratory flow rate | 23 L/min |
| PaO2 | 62 mm Hg |
| PaCO2 | 38 mm Hg |
1. What is the disorder of this 62-year-old man?
2. Is this primarily a restrictive or an obstructive disorder?Why?
3. Why is the bronchodilator therapy ineffective in thisman?
4. What causes the hypoxemia?
6. What is the cause of this altered RV?
7. Calculate the tidal volume (TV) for this person before andafter the bronchodilator therapy.
8. Is each TV normal or altered?
9. Calculate the minute ventilation (MV) for this person beforeand after the bronchodilator therapy.
10. Is each MV normal or altered?
